You can use
dateutil.parser.parse to parse strings into datetime objects.
dateutil.parser.parse will attempt to guess the format of your string, if you know the exact format in advance then you can use
datetime.strptime which you supply a format string to (see Brent Washburne's answer).
from dateutil.parser import parse a = "2012-10-09T19:00:55Z" b = parse(a) print(b.weekday()) # 1 (equal to a Tuesday)